1. Field of the Invention
The present invention relates to a color photosensitive material, which is used for image formation in a heat development process.
2. Description of the Related Art
It is known that a silver halide photographic photosensitive material can form images by heat development. This is described, for example, in xe2x80x9cFundamentals of Photographic Engineeringxe2x80x94Non-silver Salt Photography Sectionxe2x80x9d, pp. 242-255, Corona Co., Ltd., 1982, U.S. Pat. No. 4,500,626, and so on. A heat development type photosensitive material utilizing a silver halide exhibits superior photographic characteristics such as sensitivity and gradation in comparison with a photosensitive material for use in an electronic photography, a diazo photography, or the like. As to methods for obtaining images by heat development of a silver halide photosensitive material, a variety of methods have been proposed. One of these methods is a color development process in which dye images are formed by a coupling reaction between the oxidized form of a developing agent and a coupler. As to the developing agents and the couplers usable in this color development process, there have been made various proposals. For example, U.S. Pat. No. 3,531,256 proposes a combination of a reducing agent based on p-phenylenediamine and a phenol or active methylene coupler; U.S. Pat. No. 3,761,270 proposes a reducing agent based on p-aminophenol; and U.S. Pat. No. 4,021,240 proposes a combination of a reducing agent based on sulfonamide phenol and a 4-equivalent coupler.
However, in the conventional heat development processes described above, undeveloped silver halides, which remain in photosensitive materials even after processing, form colors at the time of printout or with the passage of time. In addition, since reduced silver and the color images are present simultaneously in exposed regions, defects such as color muddiness are sometimes caused. In order to solve these problems, there has been proposed a heat development process based on a dye transfer system in which diffusive dyes are formed by heat development and the dyes thus formed are transferred to an image-receiving layer. For example, there has been proposed a process in which a compound comprising a dye-releasable material having a diffusive dye which has already formed color fixed thereto is incorporated into a photosensitive material so that, when the photosensitive material undergoes heat development, the diffusive dyes are diffused image-wise and transferred to an image-receiving layer (U.S. Pat. Nos. 4,500,625, 4,483,914, 4,503,137, and 4,559,290, Japanese Patent Application Laid-Open (JP-A) Nos. 58-149046, 60-133449, 59-218443, and 61-238056, European Patent Laid-Open No. 220,746A2, Journal of Technical Disclosure No.87-6199, European Patent Laid-Open No. 210660A2, and so on). This process is excellent in that both of a negative color image and a positive color image can be obtained by changing the kinds of the dye-releasable compounds or of the silver halides to be used. However, this process is associated with a problem that the sensitivity of the photosensitive material is low because a dye, which has already formed color, is fixed to the dye-releasable material in the photosensitive material.
On the other hand, also proposed is a heat development process based on a dye transfer system in which a colorless coupler and a developing agent are incorporated into a photosensitive material so that, when the photosensitive material undergoes heat development, the colorless coupler and the developing agent react with each other to form diffusive dyes image-wise which are transferred to an image-receiving layer. For example, Japanese Patent Application Publication (JP-B) No. 63-36487, and JP-A Nos. 5-224381 and 6-83005 disclose a photosensitive material for heat development which contains a color developer precursor capable of releasing p-phenylenediamine and a coupler; JP-A No. 59-111148 discloses a combination of a ureidoaniline-based reducing agent and an active methylene-type coupler; and JP-A No. 58-149047 discloses a photosensitive material utilizing a coupler having a polymeric chain in the leaving group thereof and releasing a diffusive dye in color development. These processes, which do not need to contain dyes, which have formed color in the photosensitive material, are excellent in that the sensitivity is raised. However, these processes present a problem that the color formability is relatively low and it is difficult to shorten the time required for the color formation. An example of the photosensitive materials, which have solved the above-mentioned problem, is a photosensitive material proposed in JP-A No. 9-152705 in which a dye is formed/released by a combination of a carbamoylhydrazine-based developing agent and an active methylene-type coupler. This process is excellent in color formability and in short period processability. However, improvement of this process is necessary because the color formability of cyan images in particular is still insufficient when images are formed by transfer.
The object of the present invention is to provide a heat developable color photosensitive material, characterized by good color formability, rapid processing and capability to form colors with reduced color muddiness.
In a first aspect of the present invention, there is provided a heat developable color photosensitive material, said material comprising a support having disposed thereon a photosensitive layer including at least two layers, any one of the layers containing a photosensitive silver halide, a binder, and an incorporated color developing agent, one layer containing a substantially colorless coupler which forms a diffusive dye by coupling with the oxidized form of the incorporated developing agent, another layer containing a compound represented by the general formula (1), wherein the hue of the diffusive dye, which is formed by the coupling reaction between the substantially colorless compound and the oxidized form of the incorporated color developing agent, and the hue of the diffusive dye residue, which is represented by Dye in the general formula (1), differ from each other and the general formula (1) being as follows:
Cp-(L)n-Dyexe2x80x83xe2x80x83General formula (1)
wherein Cp represents a coupler residue, L represents a bivalent linking group, n is 0 or 1, Dye represents a diffusive dye residue, and -(L)n-Dye is linked to the active site of coupling.
In a second aspect of the present invention, there is provided A heat developable color photosensitive material, said material comprising a support having disposed thereon a first photosensitive layer sensitive to the light of a first wavelength region xcex1 and a second photosensitive layer sensitive to the light of a second wavelength region xcex2, wherein the first photosensitive layer contains a photosensitive silver halide sensitive to the light of the region xcex1, a binder, an incorporated color developing agent, and a substantially colorless coupler which forms a diffusive dye by coupling with the oxidized form of the incorporated developing agent while the second photosensitive layer contains a photosensitive silver halide sensitive to the light of the region xcex2, a binder, an incorporated color developing agent, and a compound represented by the following general formula (1), wherein xcex1 is not equal to xcex2, wherein the hue of the diffusive dye, which is formed by the coupling reaction between the substantially colorless compound and the oxidized form of the incorporated color developing agent, and the hue of the diffusive dye residue, which is represented by Dye in the general formula (1), differ from each other, and the general formula (1) being as follows:
Cp-(L)n-Dyexe2x80x83xe2x80x83General formula (1)
wherein Cp represents a coupler residue, L represents a bivalent linking group, n is 0 or 1, Dye represents a diffusive dye residue, and -(L)n-Dye is linked to the active site of coupling.
In both the first and second aspect, the Cp is preferably selected from the coupler residues represented by the following general formulae (4) to (9): 
wherein R6 and R7 each represents independently an aryl group, a heterocyclic group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group, a carbamoyl group, a sulfamoyl group, a cyano group, a sulfonyl group, or a sulfinyl group, R6 and R7 may join together to form a 5-, 6-, or 7-membered ring, R6 and R7 may not be an aryl group at the same time; and -* indicates the site to which -(L)n-Dye bonds; 
wherein R8 represents a hydrogen atom or a substituent group; R9 represents an alkyl group, an aryl group, or a heterocyclic group; and -* indicates the site to which -(L)n-Dye bonds 
wherein R10 represents a hydrogen atom or a substituent group; and Za and Zb independently represents xe2x80x94Nxe2x95x90 or xe2x80x94C(R11)xe2x95x90; R11 represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group; and -* indicates the site to which -(L)n-Dye bonds; 
wherein R12, R13, R14, and R15 independently represents a hydrogen atom or a substituent group and R14 and R15may join together to form a 5-, 6-, or 7-membered saturated ring; and -* indicates the site to which -(L)n-Dye bonds; 
wherein R16 represents a hydrogen atom or a substituent group; R17 represents a substituent group; m is an integer of 0 to 4; and -* indicates the site to which -(L)n-Dye bonds; 
wherein R18 and R19 independently represents a hydrogen atom or a substituent group; Zc and Zd independently represents xe2x80x94Nxe2x95x90 or xe2x95x90C(R20)xe2x80x94; R20 represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group; and -* indicates the site to which -(L)n-Dye bonds.